Tumor-specific mutated antigenic peptide presented by MHC class I molecule

A tumor-specific mutated antigenic peptide presented by an MHC class I molecule is a short peptide (typically 8–11 amino acids) derived from a somatic mutation unique to a cancer cell, bound to a major histocompatibility complex class I (MHC I) protein on the tumor cell surface[5][9]. This complex allows cytotoxic T lymphocytes (CD8+ T cells) to recognize and specifically target tumor cells, as these mutated peptides (also referred to as neoantigens) are not present in normal tissues[9][5]. MHC class I molecules are transmembrane glycoproteins (such as HLA-A, HLA-B, or HLA-C in humans) that sample endogenous peptides through proteasomal processing, transport via TAP, and complex assembly in the endoplasmic reticulum before trafficking to the cell surface[4][6][10]. The presentation of mutant antigens is central to tumor immunosurveillance and provides a molecular basis for T cell–mediated cancer immunotherapy, including immune checkpoint blockade, TCR-mimetic antibodies, peptide vaccines, and engineered T cell therapies[3][5]. Loss of the antigen, or defects in MHC I expression, are a major route for cancer immune evasion[1].

Other names

Tumor-specific neoantigen-MHC class I complexTumor neoepitope–MHC class I complexMutated antigenic peptide–MHC class I complexNeoantigen–MHC class I complex

Targeting of presented neoantigen for recognition and destruction by cytotoxic T lymphocytes (CTLs) Drug- or antibody-mediated stimulation of CTL recognition (e.g., bispecific T cell engagers, CAR-T) Checkpoint blockade restores CTL function against these complexes